阅读说明：本技术 一种超高强度恒弹性合金及其制备方法 (Ultrahigh-strength constant-elasticity alloy and preparation method thereof ) 是由 于一鹏 钟振前 张敬霖 吴滨 卢凤双 罗曦 张建生 张建福 于 2020-04-23 设计创作，主要内容包括：本发明涉及一种超高强度恒弹性合金及其制备方法,该合金的化学成分按重量百分比表示为：Ni 16.0～21.0、Co 7.0～13.5、W 0.05～3、Mo 3～6、Nb 0.05～0.5、Ti 0.35～1.0、Al 0.05～0.3、P＜0.01、S＜0.01,余量为Fe；所述合金采用真空感应熔炼+真空自耗重熔→锻造成形→循环相变热处理→固溶处理→回火处理工艺制备。本发明在FeNiCoMoTiAl系合金的基础上,添加适量的W、Nb元素,通过调整制备方法,选择合适的时效热处理,获得的合金在20℃～100℃的温度范围,抗拉强度高于1510MPa,频率温度系数≤20×10<Sup>-6</Sup>/℃。(The invention relates to an ultrahigh-strength constant-elasticity alloy and a preparation method thereof, wherein the alloy comprises the following chemical components in percentage by weight: 16.0 to 21.0 Ni, 7.0 to 13.5 Co, 0.05 to 3W, 3 to 6 Mo, 0.05 to 0.5 Nb, 0.35 to 1.0 Ti, 0.05 to 0.3 Al, and less than 0.01PThe invention adds a proper amount of W, Nb elements on the basis of FeNiCoMoTiAl series alloy, selects proper aging heat treatment by adjusting the preparation method, and obtains the alloy with the temperature range of 20-100 ℃, the tensile strength higher than 1510MPa, the frequency temperature coefficient less than or equal to 20 × 10 and the temperature coefficient less than or equal to 20 × ‑6 /℃。)

1. An ultrahigh-strength constant-elasticity alloy is characterized in that: the alloy comprises the following chemical components in percentage by weight: 16.0 to 21.0 percent of Ni, 7.0 to 13.5 percent of Co, 0.05 to 3 percent of W, 3 to 6 percent of Mo, 0.05 to 0.5 percent of Nb, 0.35 to 1.0 percent of Ti, 0.05 to 0.3 percent of Al, less than 0.01 percent of P, less than 0.01 percent of S and the balance of Fe.

2. The ultra-high strength, constant elasticity alloy of claim 1, wherein: 16.3 to 20.8 Ni, 7.7 to 13.1 Co, 0.6 to 2.6W, 3.5 to 5.5 Mo, 0.1 to 0.44 Nb, 0.39 to 0.85 Ti, 0.07 to 0.25 Al, less than 0.002P, less than 0.002S, and the balance Fe.

3. The ultra-high strength, constant elasticity alloy of claim 1, wherein:

the alloy is prepared by adopting the processes of vacuum induction melting, vacuum consumable remelting → forging forming → cyclic phase change heat treatment → solution treatment → tempering treatment.

4. The ultra-high strength constant elasticity alloy according to claim 1, wherein the alloy has a room temperature tensile strength Rm of more than 1480MPa and a temperature coefficient of frequency | β_{f(20℃～100℃)}|≤20×10^-6/℃。

5. The ultrahigh-strength constant-elasticity alloy as claimed in claim 2, wherein the tensile strength Rm at room temperature of the alloy is 1510-1610 MPa, and the temperature coefficient of frequency is | β_{f(20℃～100℃)}|≤15×10^-6/℃。

6. The ultra-high strength, constant elasticity alloy of claim 1, wherein: the alloy, in use, has one or more of the following microstructures:

the gamma' precipitate phase formed by Nb with Ni, Co, i.e. Ni (Co)₃A Nb phase; (ii) a

The gamma-prime precipitate phase of Ti with Ni, Co, i.e. Ni (Co)₃A Ti phase;

gamma prime precipitates of Al with Ni and Co, i.e. Ni (Co)₃An Al phase;

the gamma' precipitate phase may also be Ni (Co)₃A Ti (Al) phase.

7. The ultra-high strength, constant elasticity alloy of claim 1, wherein: the grain size of the alloy in a use state is 9-11 grades.

8. A method of producing an ultra-high strength, constant elasticity alloy according to any of claims 1 to 7, wherein: the method comprises the following steps:

(1) raw material preparation

Preparing alloy raw materials including 16.0-21.0 wt% of Ni, 7.0-13.5 wt% of Co, 0.05-3 wt% of W, 3-6 wt% of Mo, 0.05-0.5 wt% of Nb, 0.35-1.0 wt% of Ti, 0.05-0.3 wt% of Al, less than 0.01 wt% of P, less than 0.01 wt% of S and the balance Fe;

(2) melting

Smelting alloy in a vacuum induction furnace with vacuum degree not greater than 1 × 10Pa, in which Fe, Ni, Co, W and Mo are fed directly into crucible as the first material and Nb, Ti and Al are fed into the hopper of the vacuum induction furnace as the second material, refining for certain time after the materials are cleaned, casting molten steel in the vacuum chamber of the vacuum induction furnace to form electrode rod, and vacuum self-cleaning the electrode rodRemelting at vacuum degree of 1 × 10 or less^-1Pa, forming a consumable ingot;

(3) hot forging

After peeling the consumable ingot, charging the consumable ingot at the temperature lower than 700 ℃; controlling the heating rate at 100-200 ℃ per hour, keeping the temperature at 1100 +/-10 ℃ for a certain time, and forging the blank into a required specification during cogging;

(4) thermal treatment

The alloy after hot forging is subjected to 900 +/-50 ℃ cyclic phase change heat treatment, and the grain size is controlled to be more than 8 grade;

(5) solution treatment

Then carrying out solution treatment for 1 plus or minus 0.2h at the temperature of 810 plus or minus 50 ℃;

(6) tempering treatment

And finally, preserving the heat at the temperature of between 50 and 625 ℃ for 4 hours to carry out vacuum aging treatment to obtain the final ultrahigh-strength constant-elasticity alloy.

Technical Field

The invention relates to an ultrahigh-strength constant-elasticity alloy and a preparation method thereof, wherein the ultrahigh-strength constant-elasticity alloy has higher strength and lower frequency temperature coefficient in the temperature range of 20-100 ℃.

Background

The FeNiCoMoTiAl alloy is a precipitation hardening ultrahigh-strength alloy, precipitation phases are separated out on a martensite matrix to improve the alloy strength by generally utilizing aging heat treatment, the room-temperature tensile strength Rm can reach over 1800MPa, the martensite frequency temperature coefficient in the alloy is negative, the martensite is reversed to be austenite at the increased aging temperature, and the frequency temperature coefficient of the reversed austenite is positive.

Disclosure of Invention

The invention aims to obtain the ultrahigh-strength constant-elasticity alloy and the preparation method thereof by improving the components of the alloy, namely, on the basis of FeNiCoMoTiAl alloy, a proper amount of W, Nb element is added, and the preparation method is adjusted and a proper aging heat treatment is selected to obtain the alloy with the room-temperature tensile strength higher than 1510MPa and the frequency temperature coefficient of | β_{f(20℃～100℃)}|≤20×10^-6The performance of the alloy can be kept unchanged while the content of alloy elements is reduced.

In order to achieve the purpose, the invention provides the following technical scheme:

an ultrahigh-strength constant-elasticity alloy comprises the following chemical components in percentage by weight: 16.0 to 21.0 Ni, 7.0 to 13.5 Co, 0.05 to 3W, 3 to 6 Mo, 0.05 to 0.5 Nb, 0.35 to 1.0 Ti, 0.05 to 0.3 Al, less than 0.01P, less than 0.01S, and the balance Fe.

Preferably, Ni 16.3-20.8, Co 7.7-13.1, W0.6-2.6, Mo 3.5-5.5, Nb 0.1-0.44, Ti 0.39-0.85, Al 0.07-0.25, P < 0.002, S < 0.002, and the balance Fe.

The alloy is prepared by adopting the processes of vacuum induction melting, vacuum consumable remelting → forging forming → cyclic phase change heat treatment → solution treatment → tempering treatment.

The room temperature tensile strength Rm of the alloy is more than 1480MPa, and the frequency temperature coefficient | β_{f(20℃～100℃)}|≤20×10^-6/℃。

Preferably, the room-temperature tensile strength Rm of the alloy is 1510-1610 MPa, and the frequency temperature coefficient | β_{f(20℃～100℃)}|≤15×10^-6/℃。

The alloy, in use, has one or more of the following microstructures:

the gamma' precipitate phase formed by Nb with Ni, Co, i.e. Ni (Co)₃A Nb phase; (ii) a

The gamma-prime precipitate phase of Ti with Ni, Co, i.e. Ni (Co)₃A Ti phase;

gamma prime precipitates of Al with Ni and Co, i.e. Ni (Co)₃An Al phase;

the above-mentionedThe gamma' precipitate phase may also be Ni (Co)₃A Ti (Al) phase.

The grain size of the alloy in a use state is 9-11 grades.

A preparation method of an ultrahigh-strength constant-elasticity alloy comprises the following steps:

(1) raw material preparation

Preparing alloy raw materials including 16.0-21.0 wt% of Ni, 7.0-13.5 wt% of Co, 0.05-3 wt% of W, 3-6 wt% of Mo, 0.05-0.5 wt% of Nb, 0.35-1.0 wt% of Ti, 0.05-0.3 wt% of Al, less than 0.01 wt% of P, less than 0.01 wt% of S and the balance Fe;

(2) melting

Smelting alloy in a vacuum induction furnace with vacuum degree not greater than 1 × 10Pa, smelting Fe, Ni, Co, W and Mo as the first material, feeding into crucible, smelting Nb, Ti and Al as the second material, refining for certain time, casting molten steel in the vacuum chamber of the vacuum induction furnace to form electrode rod, vacuum consumable remelting to reach vacuum degree not greater than 1 × 10Pa^-1Pa, forming a consumable ingot;

(3) hot forging

After peeling the consumable ingot, charging the consumable ingot at the temperature lower than 700 ℃; controlling the heating rate at 100-200 ℃ per hour, keeping the temperature at 1100 +/-10 ℃ for a certain time, and forging the blank into a required specification during cogging;

(4) thermal treatment

The alloy after hot forging is subjected to 900 +/-50 ℃ cyclic phase change heat treatment, and the grain size is controlled to be more than 8 grade;

(5) solution treatment

Then carrying out solution treatment for 1 plus or minus 0.2h at the temperature of 810 plus or minus 50 ℃;

(6) tempering treatment

And finally, preserving the heat at the temperature of between 50 and 625 ℃ for 4 hours to carry out vacuum aging treatment to obtain the final ultrahigh-strength constant-elasticity alloy.

The key point of the invention is that on the basis of the prior FeNiCoMoTiAl alloy, W, Nb elements are added into the alloy, and the alloy is smelted, forged and thermally treated to obtain the ultrahigh-strength and low-frequency temperature coefficient alloy within the temperature range of 20-100 ℃.

The functions of the alloying elements and the alloy design are as follows:

ni, Co: a primary alloying element;

w, Mo: form a solid solution with Fe element, and the solid solution strengthening effect is achieved;

nb: the main strengthening element, forming a gamma' precipitation phase with Ni and Co, i.e. Ni (Co)₃A Nb phase;

ti: the main strengthening element forms a gamma' precipitation phase with Ni and Co, namely Ni (Co)₃A Ti phase;

al is a strengthening element which forms a gamma' precipitate phase with Ni and Co, i.e. Ni (Co)₃An Al phase;

p, S: the lower the content of the impurity element, the better.

Wherein, W atom size is larger than Mo, lattice distortion effect caused by solid solution is larger than Mo, stronger solid solution strengthening effect is achieved, and Mo can be replaced by partial W. Nb is added into the alloy, and gamma' (Ni (Co))₃Nb), the precipitation strengthening effect of the alloy aging treatment can be further improved.

The gamma' precipitate phase may also be Ni (Co)₃A Ti (Al) phase, in which Ni and Co may be substituted for each other, and Ti and Al may be substituted for each other in the γ' precipitate phase crystal structure.

Compared with the prior art, the invention has the beneficial effects that:

the ultrahigh-strength constant-elasticity alloy disclosed by the invention is prepared by adjusting the alloy components and the preparation method and selecting appropriate aging heat treatment to obtain the ultrahigh-strength constant-elasticity alloy with the room-temperature tensile strength higher than 1510MPa and the frequency temperature coefficient of | β_{f(20℃～100℃)}|≤20×10^-6The alloy solid solution strengthening and precipitation strengthening effects are improved and the alloy strength is improved by adding W, Nb elements at the temperature of/° C.

Detailed Description

The present invention will be further illustrated with reference to the following examples.

The invention relates to an ultrahigh-strength constant-elasticity alloy, which is obtained by adding a proper amount of W, Nb on the basis of FeNiCoMoTiAl ultrahigh-strength alloy and controlling the temperature to be 20-100 ℃.

The compositions of the alloys to which the present invention relates are shown in table 1.

TABLE 1 ultra-high Strength constant elasticity alloy compositions

Composition (I)	Content (wt%)
		Ni	16.0～21.0
Co	7.0～13.5
		W	0.05～3
Mo	3～6
		Nb	0.05～0.5
Ti	0.35～1.0
		Al	0.05～0.3
P	＜0.01
		S	＜0.01
Fe	Balance of

The preparation method of the invention comprises the following steps:

melting

Smelting alloy in a vacuum induction furnace with the vacuum degree of less than or equal to 1 × 10Pa, and strictly controlling the burning loss of alloy elements in the smelting process to control the components of the alloy within the design range, wherein Fe, Ni, Co, W and Mo are directly put into a crucible as primary feeding materials, Nb, Ti and Al are put into a vacuum induction furnace hopper as secondary feeding materials, refining is carried out for 10 minutes after all raw materials are melted and cleaned, then molten steel is cast into an electrode bar in a vacuum chamber of the vacuum induction furnace, the electrode bar is subjected to vacuum consumable remelting, and the vacuum degree is less than or equal to 1 × 10^-1Pa, forming a consumable ingot.

Hot forging

And (4) after peeling the consumable ingot, charging the consumable ingot at the temperature lower than 700 ℃. The heating rate is controlled to be 100-200 ℃ per hour, and after the temperature is kept for a proper time at 1100 +/-10 ℃, the blank is forged into the required specification during cogging.

Thermal treatment

The hot forging alloy is subjected to 900 ℃ cyclic phase change heat treatment, and the grain size is controlled to be above 8 grade.

Solution treatment

Then the solution treatment is carried out for × 1h at 810 ℃.

Tempering treatment

Finally, the temperature is kept at 50-625 ℃ for 4 hours for vacuum aging treatment.